Open Library API
Open Library books API: edition lookup by ISBN.
Operational
Last checked · response time 457 ms
90-day uptime
Monitoring since · 32 days of data
Past incidents
No incidents reported.
No incidents reported.
No incidents reported.
No incidents reported.
No incidents reported.
No incidents reported.
No incidents reported.
- Guardian-measuredResolvedAPI: HTTP 503 · resolved after 4m
- Availability incidentEndpoint has failed 3 consecutive polls (latest: HTTP 503)
- Guardian-measuredResolvedAPI: HTTP 503 · resolved after 25m
- Availability incidentEndpoint has failed 3 consecutive polls (latest: HTTP 503)
- Guardian-measuredResolvedAPI: HTTP 503 · resolved after 10m
- Guardian-measuredResolvedAPI: HTTP 503 · resolved after 5m
No incidents reported.
No incidents reported.
- Guardian-measuredResolvedAPI: HTTP 503 · resolved after 4m
- Guardian-measuredResolvedAPI: HTTP 503 · resolved after 5m
- Guardian-measuredResolvedAPI: HTTP 503 · resolved after 4m
- Guardian-measuredResolvedAPI: HTTP 521 · resolved after 5m
No incidents reported.
- Guardian-measuredResolvedAPI: HTTP 521 · resolved (start not recorded)
- Availability incidentEndpoint has failed 3 consecutive polls (latest: HTTP 521)
Recent changes
No changes detected in 32 days of monitoring (since 2026-06-11).
Integrate
The live status, 90-day uptime figure and change history on this page are also machine-readable: embed the badge, poll the JSON, or subscribe to the feed. No key needed.
Status badge: 
Markdown embed: [](https://guardiandev.ai/apis/openlibrary-api)
Machine-readable: JSON (versioned v1, CORS-enabled) · Atom feed of drift & outage events.
Guardian probes https://openlibrary.org/isbn/9780140328721.json about every 5 minutes. How Guardian measures.